On 12/13/2018 01:19 PM, Quentin Monnet wrote:
> Similarly to what was done for program types and map types, add a set of
> probes to test the availability of the different eBPF helper functions
> on the current system.
>
> Sample output:
>
> # bpftool feature probe kernel
> ...
> Scanning eBPF helper functions...
> eBPF helper bpf_map_lookup_elem is available
> eBPF helper bpf_map_update_elem is available
> eBPF helper bpf_map_delete_elem is available
> ...
>
> # bpftool --json --pretty feature probe kernel
> {
> ...
> "helpers": {
> "have_bpf_map_lookup_elem_helper": true,
> "have_bpf_map_update_elem_helper": true,
> "have_bpf_map_delete_elem_helper": true,
> ...
> }
> }
>
> # bpftool feature probe kernel macros prefix BPFTOOL_
> ...
> /*** eBPF helper functions ***/
> #define BPFTOOL_BPF_MAP_LOOKUP_ELEM_HELPER
> #define BPFTOOL_BPF_MAP_UPDATE_ELEM_HELPER
> #define BPFTOOL_BPF_MAP_DELETE_ELEM_HELPER
Small nit: instead of BPFTOOL_ prefix, would it make sense
to generally use Have_ prefix (similar to json output). The
former seems somewhat bpftool related though it solely probes
the underlying kernel.
> ...
>
> Signed-off-by: Quentin Monnet <quentin.mon...@netronome.com>
> Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
> ---
> .../bpftool/Documentation/bpftool-feature.rst | 4 +
> tools/bpf/bpftool/feature.c | 152 ++++++++++++++++++
> 2 files changed, 156 insertions(+)
>
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-feature.rst
> b/tools/bpf/bpftool/Documentation/bpftool-feature.rst
> index 23920a7490e9..083d30510cce 100644
> --- a/tools/bpf/bpftool/Documentation/bpftool-feature.rst
> +++ b/tools/bpf/bpftool/Documentation/bpftool-feature.rst
> @@ -39,6 +39,10 @@ DESCRIPTION
> names when including the output of this command as a header
> file.
>
> + Note that when probed, some eBPF helpers (e.g.
> + **bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
> + print warnings to kernel logs.
> +
> **bpftool feature help**
> Print short help message.
>
> diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
> index 85928f172413..77221fff6ba9 100644
> --- a/tools/bpf/bpftool/feature.c
> +++ b/tools/bpf/bpftool/feature.c
> @@ -24,6 +24,113 @@ enum probe_component {
> COMPONENT_KERNEL,
> };
>
> +#define MAX_HELPER_NAME_LEN 32
> +struct helper_param {
> + enum bpf_prog_type progtype;
> + const char name[MAX_HELPER_NAME_LEN];
> +};
> +
> +/* helper_progtype_and_name[index] associates to the BPF helper function of
> id
> + * "index" a name and a program type to run this helper with. In order to
> probe
> + * helper availability for programs offloaded to a network device, use
> + * offload-compatible types (e.g. XDP) everywhere we can. Caveats: helper
> + * probing may fail currently if only TC (but not XDP) is supported for
> + * offload.
> + */
> +static const struct helper_param helper_progtype_and_name[] = {
> + { BPF_PROG_TYPE_XDP, "no_helper_with_id_0" },
> + { BPF_PROG_TYPE_XDP, "bpf_map_lookup_elem" },
> + { BPF_PROG_TYPE_XDP, "bpf_map_update_elem" },
> + { BPF_PROG_TYPE_XDP, "bpf_map_delete_elem" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_probe_read" },
> + { BPF_PROG_TYPE_XDP, "bpf_ktime_get_ns" },
> + { BPF_PROG_TYPE_XDP, "bpf_trace_printk" },
> + { BPF_PROG_TYPE_XDP, "bpf_get_prandom_u32" },
> + { BPF_PROG_TYPE_XDP, "bpf_get_smp_processor_id" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_store_bytes" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_l3_csum_replace" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_l4_csum_replace" },
> + { BPF_PROG_TYPE_XDP, "bpf_tail_call" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_clone_redirect" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_current_pid_tgid" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_current_uid_gid" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_current_comm" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_cgroup_classid" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_vlan_push" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_vlan_pop" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_get_tunnel_key" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_set_tunnel_key" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_perf_event_read" },
> + { BPF_PROG_TYPE_XDP, "bpf_redirect" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_route_realm" },
> + { BPF_PROG_TYPE_XDP, "bpf_perf_event_output" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_load_bytes" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_stackid" },
> + { BPF_PROG_TYPE_XDP, "bpf_csum_diff" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_get_tunnel_opt" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_set_tunnel_opt" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_change_proto" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_change_type" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_under_cgroup" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_hash_recalc" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_current_task" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_probe_write_user" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_current_task_under_cgroup" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_change_tail" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_pull_data" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_csum_update" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_set_hash_invalid" },
> + { BPF_PROG_TYPE_XDP, "bpf_get_numa_node_id" },
> + { BPF_PROG_TYPE_SK_SKB, "bpf_skb_change_head" },
> + { BPF_PROG_TYPE_XDP, "bpf_xdp_adjust_head" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_probe_read_str" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_socket_cookie" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_get_socket_uid" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_set_hash" },
> + { BPF_PROG_TYPE_SOCK_OPS, "bpf_setsockopt" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_adjust_room" },
> + { BPF_PROG_TYPE_XDP, "bpf_redirect_map" },
> + { BPF_PROG_TYPE_SK_SKB, "bpf_sk_redirect_map" },
> + { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_map_update" },
> + { BPF_PROG_TYPE_XDP, "bpf_xdp_adjust_meta" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_perf_event_read_value" },
> + { BPF_PROG_TYPE_PERF_EVENT, "bpf_perf_prog_read_value" },
> + { BPF_PROG_TYPE_SOCK_OPS, "bpf_getsockopt" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_override_return" },
> + { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_ops_cb_flags_set" },
> + { BPF_PROG_TYPE_SK_MSG, "bpf_msg_redirect_map" },
> + { BPF_PROG_TYPE_SK_MSG, "bpf_msg_apply_bytes" },
> + { BPF_PROG_TYPE_SK_MSG, "bpf_msg_cork_bytes" },
> + { BPF_PROG_TYPE_SK_MSG, "bpf_msg_pull_data" },
> + { BPF_PROG_TYPE_CGROUP_SOCK_ADDR, "bpf_bind" },
> + { BPF_PROG_TYPE_XDP, "bpf_xdp_adjust_tail" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_get_xfrm_state" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_stack" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_load_bytes_relative" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_fib_lookup" },
> + { BPF_PROG_TYPE_SOCK_OPS, "bpf_sock_hash_update" },
> + { BPF_PROG_TYPE_SK_MSG, "bpf_msg_redirect_hash" },
> + { BPF_PROG_TYPE_SK_SKB, "bpf_sk_redirect_hash" },
> + { BPF_PROG_TYPE_LWT_IN, "bpf_lwt_push_encap" },
> + { BPF_PROG_TYPE_LWT_SEG6LOCAL, "bpf_lwt_seg6_store_bytes" },
> + { BPF_PROG_TYPE_LWT_SEG6LOCAL, "bpf_lwt_seg6_adjust_srh" },
> + { BPF_PROG_TYPE_LWT_SEG6LOCAL, "bpf_lwt_seg6_action" },
> + { BPF_PROG_TYPE_LIRC_MODE2, "bpf_rc_repeat" },
> + { BPF_PROG_TYPE_LIRC_MODE2, "bpf_rc_keydown" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_cgroup_id" },
> + { BPF_PROG_TYPE_KPROBE, "bpf_get_current_cgroup_id" },
> + { BPF_PROG_TYPE_CGROUP_SKB, "bpf_get_local_storage" },
> + { BPF_PROG_TYPE_SK_REUSEPORT, "bpf_sk_select_reuseport" },
> + { BPF_PROG_TYPE_SCHED_CLS, "bpf_skb_ancestor_cgroup_id" },
> + { BPF_PROG_TYPE_SK_SKB, "bpf_sk_lookup_tcp" },
> + { BPF_PROG_TYPE_SK_SKB, "bpf_sk_lookup_udp" },
> + { BPF_PROG_TYPE_SK_SKB, "bpf_sk_release" },
> + { BPF_PROG_TYPE_XDP, "bpf_map_push_elem" },
> + { BPF_PROG_TYPE_XDP, "bpf_map_pop_elem" },
> + { BPF_PROG_TYPE_XDP, "bpf_map_peek_elem" },
> + { BPF_PROG_TYPE_SK_MSG, "bpf_msg_push_data" },
Some of these helpers like bpf_perf_event_output are available on
multiple types; should they all be tested in case the one probed
prog type would not be available on the underlying kernel?
Thanks,
Daniel
